This SBIR Phase I research is for a flexible navigation system for deep space operations that does not require GPS measurements. The navigation solution is computed using an Unscented Kalman Filter that can accept any combination of range, range-rate, planet chordwidth, and angle measurements using any celestial object. The UKF employs a full nonlinear dynamical model of the orbit including gravity models and disturbance models. The filter will estimate both states and parameters. The sensor employs three methods for getting position information. The first is from chordwidth measurements of the Sun. This camera always looks at the solar disk. The second camera measures the angles between planets in the solar system. The center measures the angle from planetary centroid to planetary centroid. The third sensor measures angles between stars and the Sun vector. Each snapshot from the system provides a 3-axis measurement.
The navigation system is being developed by Princeton Satellite Systems and the sensor is being developed by Professor Michael Littman of Princeton University. A complete navigation simulation and preliminary sensor mechanical drawings will be delivered at the end of Phase I.
This plot compares the output of the navigation simulation with JPL's Horizons orbit propagator.
See the movie of an deep space trajectory at Deep Space Simulation